[Federal Register: April 21, 2006 (Volume 71, Number 77)]
[Proposed Rules]
[Page 20607-20624]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21ap06-21]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition to Delist the Pacific Coast Population of the Western
Snowy Plover
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 12-month petition finding.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
12-month finding on a petition to remove the Pacific coast population
of the western snowy plover (Charadrius alexandrinus nivosus) from the
Federal List of Threatened and Endangered Wildlife pursuant to the
Endangered Species Act of 1973, as amended. After reviewing the best
scientific and commercial information available, we find that the
petitioned action is not warranted. We ask the public to submit to us
any new information that becomes available concerning the status of, or
threats to, the species. This information will help us monitor and
encourage the conservation of this species.
DATES: The finding announced in this document was made on April 21,
2006.
ADDRESSES: Data, information, comments, or questions concerning this
finding may be sent to the Field Supervisor (Attn: WSP-DELIST), Arcata
Fish and Wildlife Office, U.S. Fish and Wildlife Service, 1655 Heindon
Road, Arcata, California 95521-5582 (fax: 707-822-8411). The petition
and supporting information are available for public inspection, by
appointment, during normal business hours, at the above address.
FOR FURTHER INFORMATION CONTACT: Jim Watkins, Fish and Wildlife
Biologist, in Arcata (telephone: 707-822-7201).
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Endangered Species Act (Act) of 1973, as
amended (16 U.S.C. 1531 et seq.) requires that we make a finding on
whether a petition to list, delist, or reclassify a species presents
substantial information to indicate the petitioned action may be
warranted. Section 4(b)(3)(B) of the Act requires that within 12 months
after receiving a petition to revise the List of Threatened and
Endangered Wildlife and Plants that contains substantial information
indicating that the petitioned action may be warranted, the Secretary
shall make one of the following findings: (a) The petitioned action is
not warranted, (b) the petitioned action is warranted, or (c) the
petitioned action is warranted but precluded by higher priority
workload. Such 12-month findings are to be published promptly in the
Federal Register.
Previous Federal Action
The Pacific coast population of the western snowy plover
(Charadrius alexandrinus nivosus) (Pacific Coast WSP) was listed as
threatened on March 5, 1993 (Service 1993 (58 FR 12864)), prior to
publication of our 1996 distinct population segment (DPS) policy
(Service and NMFS 1996a (61 FR 4722; February 7, 1996)). At the time of
listing, the primary threat to the plover was the loss and degradation
of habitat from human activities. Critical habitat for the Pacific
Coast WSP was designated on September 9, 2005 (70 FR 56969).
On July 29, 2002, we received a petition from the Surf-Ocean Beach
Commission of Lompoc, California, to delist the Pacific Coast WSP
pursuant to the Act. We also received a similar petition dated May 30,
2003, from the City of Morro Bay, California. As explained in our 1996
Petition Management Guidance (Service and NMFS 1996b), subsequent
petitions are treated separately only when they are greater in scope or
broaden the area of review of the first petition. The City of Morro Bay
petition repeats the same information provided in the Surf-Ocean Beach
Commission petition and was therefore treated as a comment on the first
petition received. On March 22, 2004 (69 FR 13326), we announced an
initial (90-day) finding that the petition presented substantial
information to indicate the petitioned action may be warranted, and we
initiated a status review under sections 4(b)(3)(A) and 4(c)(2)(A) of
the Act. We have now completed the status review on the species using
the best available scientific and commercial information, and have
reached a determination regarding the petitioned action. This status
review also fulfills the requirements of 4(c)(2).
Species Information
Snowy plovers are small shorebirds, about 16 centimeters (6 inches)
long, with pale brown upperparts, buff-colored bellies, and darker
patches on their shoulders and heads. Their dark gray to black legs are
a useful distinguishing feature when comparing to other plover species
(Page et al. 1995a). Two subspecies of snowy plover
[[Page 20608]]
recognized by the American Ornithological Union (AOU 1957), nest in
North America: The western snowy plover and the Cuban snowy plover
(Charadrius alexandrinus tenuirostis).
Biology and Distribution
The breeding range of the western snowy plover includes sites in
California, Oregon, Washington, Nevada, Utah, Arizona, Colorado, New
Mexico, Kansas, Oklahoma, Texas, and Baja California, central and
northeastern Mexico, as well as irregularly visited sites in
Saskatchewan, Canada; and Wyoming and Montana (Page et al. 1995a) (see
Figure 1). In 1993, we listed and defined the Pacific Coast WSP as
those western snowy plovers ``that nest adjacent to or near tidal
waters'' of the Pacific Ocean (Service 1993 (58 FR 12864)). In this
finding, we refer generally to plovers nesting at locations other than
on the Pacific coast as ``interior'' populations, even though this term
includes populations nesting on the Gulf coast. We also refer to
interior nesting populations according to whether they nest east or
west of the Rocky Mountains, on the Gulf Coast, or in central Mexico.
BILLING CODE 4310-55-P
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[GRAPHIC] [TIFF OMITTED] TP21AP06.000
BILLING CODE 4310-55-C
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The second North American subspecies, the Cuban snowy plover, nests
along the Gulf coast from Louisiana to western Florida and south
through the Caribbean (American Ornithological Union (AOU) 1957;
Service 1993 (58 FR 12864); Page et al. 1995a). The subspecific status
of populations breeding east of the Rocky Mountains, now considered to
belong to the subspecies C. a. nivosus, has been questioned. Some
consider these populations to belong more appropriately to the
subspecies C. a. tenuirostris (Warriner et al. 1986). Others consider
the subspecies C. a. tenuirostris to be a paler version of the western
snowy plover rather than a separate subspecies (Page et al. 1995a). In
this status review, we rely on the current American Ornithological
Union taxonomic classification that considers C. a. nivosus to be a
valid subspecies (AOU 1957).
Some plovers nesting on the Pacific coast migrate north or south to
other Pacific coastal wintering sites, while others stay at their
breeding sites year round. Birds nesting in the interior, west of the
Rocky Mountains (the western interior population) winter in coastal
California and Baja California, Mexico, and often commingle with the
Pacific Coast WSP. However, some individuals from the southern
California interior do not migrate (Page et al. 1995a). Plovers from
the interior east of the Rockies are migratory, probably wintering on
the Gulf Coast, except for small numbers of year-round residents in
Texas, Arizona, and New Mexico. Plovers nesting on the Gulf coast may
sometimes winter at other Gulf coast locations, while those nesting in
central Mexico are likely year-round residents (Page et al. 1995a).
The timing of the nesting season varies with location, but in
coastal California it tends to run from March through September (Page
et al. 1995a). Breeding locations tend to be sandy areas close to
water, including beaches, salt pans, alkaline playas, and gravel bars
on the tidally influenced portion of coastal rivers. Clutches, which
most commonly consist of three eggs, are laid in shallow scrapes or
depressions in the sand. Snowy plovers generally form monogamous pair
bonds and share incubation duties, but western snowy plover females
typically desert the brood shortly after hatching, and may renest with
a new male if time remains in the season to do so. Males typically care
for the young until they fledge, which takes about a month, and may
then renest with a new partner if sufficient time remains in the season
(Stenzel et al. 1994). This results in a serially polygamous breeding
system in which males may double clutch and females may triple clutch
during a single season (Page et al. 1995a).
Population Status
The current known breeding range of the Pacific Coast WSP extends
from Damon Point, Washington, to Bahia Magdelena, Baja California,
Mexico. Observed estimates for the Pacific Coast WSP, rangewide, are
approximately 3,700 individuals; within that total, the observed
estimate of the U.S. population of the Pacific Coast WSP is
approximately 1,800 adults (see Table 1) (L. Stenzel, in litt. 2004a;
G. Page, in litt. 2005b; L. Kelly, in litt. 2006; M. Jensen, in litt.
2006). Current population estimates are developed by multiplying the
number of adult plovers observed during breeding window surveys (Table
1 Observed Estimate) by a correction factor of 1.3, which adjusts the
observed number to that of a known population (Table 1 Current
Population Estimate). Multiplying the observed estimates by the
correction factor, the current population estimate for the United
States portion of the Pacific Coast WSP is approximately 2,300 (see
Table 1), based on the 2005 breeding window survey (Stenzel, in litt.
2004b; Page, in litt. 2005b; Jensen, in litt. 2006; Kelly, in litt.
2006), and the current population estimate for the Pacific Coast WSP
rangewide is approximately 4,800.
Table 1.--Observed and Estimated Numbers of Adult Western Snowy Plovers in the United States and Mexico
[Adapted and updated from Page et al. 1995a]
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Observed Observed Current population
Location Year number Source estimate \1\ estimate \2\
----------------------------------------------------------------------------------------------------------------
U.S. Pacific Coast........... 2005 .......... A 1,795 2,334.
Washington................... 2005 15 I ................ ....................
Oregon....................... 2005 100 H ................ ....................
California................... 2005 1,680 A ................ ....................
Mexico, West Coast of Baja 1991-1992 1,344 B, C At least 1,900 At least 2,470.
California.
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Pacific Coast WSP Estimated Total 3,695 4,804.
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Interior U.S., west of Rocky
Mtns.:
All States except Utah... 1988 .......... C 6,100 7,930.
Nevada................... 1988 691 C ................ ....................
Oregon................... 1988 552 C ................ ....................
California:
Great Basin.............. 1988 1,213 C ................ ....................
San Joaquin Valley....... 1988 241 C ................ ....................
S. California deserts.... 1988 291 C ................ ....................
Utah......................... 1992 1,501 D 4,189 5,445.
Great Plains:
Colorado................. 1986-92 .......... C, G Up to 150 Up to 195.
Kansas................... 1986-92 .......... C, G Up to 356 Up to 463.
Oklahoma................. 1986-92 .......... C, G 2,007 2,609.
Texas.................... 1986-92 .......... C, G 500 650.
New Mexico............... 1986-92 .......... C, G Up to 500 Up to 650.
Gulf Coast:
Texas.................... 2004 .......... E 1,000 1,300.
NE Mexico................ 1992 .......... G Up to 34 Up to 44.
Interior Mexico.............. 1994 .......... F At least 35 At least 46.
[[Page 20611]]
Presa Acecatecana........ .......... 12 ................. ................ ....................
Salinas de Hidalgo....... .......... 16 ................. ................ ....................
Jalisco (near Atoyac).... .......... 6 ................. ................ ....................
Lago Texcoco............. .......... 1 ................. ................ ....................
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Estimated Total for Interior and Gulf Coast Breeding WSP 14,871 19,332.
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Estimated Grand Total for the Subspecies 18,566 24,136.
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\1\ The Observed Estimate (Obs. Est.) is approximated for the Mexico portion of the range based upon the
research conducted by Page et al. (1995a).
\2\ The 2005 Current Population Est. equals the Obs. Est. multiplied by a correction factor of 1.3. The Obs.
Est. often under counts the actual number of birds. Research by the Point Reyes Bird Observatory shows a
correction factor is needed to give a more accurate population count (Stenzel in litt. 2004a).
Sources: A = G. Page in litt. 2005; B = E. Palacios et al. 1994; C = G. Page et al. 1995a; D = P. Paton in litt.
2004; E = Zdravkovic 2004; F = Howell and Webb 1994; G = Gorman and Haig 2002; H = L. Kelly in litt. 2006; I =
M. Jensen in litt. 2006.
Recent census data for the Baja California, Mexico population of
the Pacific Coast WSP do not exist; however, we use the observed
estimate of 1,900 adults as provided in Page et al. (1995a), as that is
the best available information. The population is sparse in Washington,
Oregon, and northern California. Historical records indicate that
nesting plovers were once more widely distributed and abundant in
coastal Washington, Oregon, and California than at present (Page et al.
1995a). At about the time the species was listed under the Act,
approximately 2,000 western snowy plovers bred along the United States
Pacific Coast (Page et al. 1995a) and approximately 1,900 bred on the
west coast of Baja California, Mexico (Palacios et al. 1994). The
largest number of breeding birds occurred from south San Francisco Bay
to southern Baja California (Page and Stenzel 1981; Palacios et al.
1994).
Washington--Occupancy of Sites: In Washington, plovers formerly
nested at five coastal sites (Washington Department of Fish and
Wildlife 1995). Three of these remain currently active, indicating a 40
percent decline in the number of Washington breeding areas. Occupancy
at sites in Washington has declined for several reasons, including site
degradation due to beach erosion (e.g., Westport Spit, Leadbetter
Point, Gunpowder Sands Island). Subsequent to the 1993 listing, habitat
conditions have improved or expanded at other sites (e.g., Midway
Beach).
Washington--Number of Pacific Coast WSP: The number of birds in
Washington, however, appear to be stable to increasing since the early
1990s, based on consistent, intensive, repeatable counts of adults
during the breeding season. Breeding season surveys indicate a general
increase in the plover breeding population since 1995 (Washington Dept.
of Fish and Wildlife, in litt. 2003). Population numbers range from a
low of 19 adults in 1994, to 68 in 2003. In recent years, sand has
built up at Midway Beach creating high quality habitat, and nesting was
documented in 1998 (Richardson et al. 2000). Uniquely banded plovers
from natal locations along the Oregon and California coasts have bred
in Washington coastal sites, adding to the overall breeding population
within the State. We attribute the increases to improved coastal
habitat at some locations, and intensive management in Oregon and
California.
Oregon--Occupancy of Sites: In Oregon, plovers historically nested
at 29 coastal locations. Our 1993 listing decision was based, in part,
on the loss of 23 of those locations (Service 1993 (58 FR 12864)).
However, in 2004, the number of breeding sites had increased to 10 due
to the reoccupation of 4 historic sites (D. Lauten, in litt. 2004). As
a result, 65 percent (19 of 29) of the historic nesting locations have
been lost; improved from 79 percent at the time of listing.
Oregon--Number of Pacific Coast WSP: Annual surveys of adult and
juvenile plovers in coastal Oregon began in 1978, with intensive
monitoring beginning in 1993. Survey data shows a general decline in
breeding adults throughout coastal Oregon until 1994, at which time the
trend reversed to an increase in breeding adults. Although the overall
breeding population trend is still down from historical numbers, the
period from 1994 to present has shown a slight increase (J. Baldwin, in
litt. 2004). Plovers from California have been observed nesting in
coastal Oregon, contributing to the State's breeding population,
estimated at 110 birds in 2003 (Oregon Department of Parks and
Recreation 2003). Eighty-three plovers were observed during breeding
surveys in 2004, and 100 were counted during the 2005 breeding season
(Lauten et al. 2006). We attribute the increase directly to protections
and resultant management from the 1993 Federal listing. Management
measures benefiting plovers include the use of exclosures to reduce
nest predation, restoration of breeding habitat by removing European
beachgrass (Ammophila arenaria), increased use of signs and symbolic
fencing (temporary post and cable) around breeding sites, intensified
public information, and enhanced law enforcement.
California--Occupancy of Sites: Eight geographic areas in
California support over three-quarters of the Statewide coastal
breeding population (Page et al. 1991). By the late 1970s, nesting
plovers in California were absent from 33 of 53 of the breeding
locations having breeding records prior to 1970 (Page and Stenzel
1981). Stenzel (in litt. 2004b) has subsequently identified an
additional 11 locations that have lost nesting plovers. An estimated
1,566 adult plovers were seen during initial Statewide coastal surveys
by Point Reyes Bird Observatory (PRBO) during the 1977 to 1980 breeding
seasons (Page and Stenzel 1981). The surveys indicated that by 1980,
plovers had been extirpated or severely reduced in breeding
distribution throughout substantial portions of their coastal southern
California breeding range, especially in San Diego, Orange, and Los
Angeles Counties. With the exception of some beach segments along
[[Page 20612]]
Monterey Bay in Monterey County, breeding plovers were absent or
severely reduced at other historic breeding sites along the southern
and central California coast. A preliminary analysis of current
breeding sites identifies 10 new, low-density breeding locations (L.
Stenzel, in litt. 2004b). However, analysis also shows that at least 44
of the historic sites, many of which were known to be high-density
sites, have not had any recent nesting activity (L. Stenzel, in litt.
2004a; 2004b).
California--Number of Pacific Coast WSP: In addition to losses of
breeding locations, or lack of activity at breeding locations,
Statewide beach surveys conducted by PRBO during 1989 and 1991 also
indicated a decline in numbers of breeding plovers. Along the
California coast, including the Channel Islands, plover numbers
declined by almost 5 percent, and the estimated decline at San
Francisco Bay was about 40 percent (A. Powell, pers. comm. 1998; Point
Reyes Bird Observatory, unpublished data). More recent surveys during
the breeding seasons of 2000, 2002, 2003, 2004, and 2005, were
accomplished through a collaboration of researchers studying plovers in
coastal California. Results are provided in Table 2, below.
Table 2.--Total Number of Adult Snowy Plovers During Breeding Season Window Surveys of the California Coast
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1977-1980
Year \1\ 1989 \2\ 1991 \3\ 2000 \3\ 2002 \3\ 2003 \3\ 2004 \3\ 2005 \4\
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Total................................................... 1,566 1,386 1,371 976 1,387 1,444 1,904 1,680
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\1\ Page and Stenzel 1981--Surveys were conducted in multiple years; \2\ Page et al. 1991; \3\ L. Stenzel, in litt. 2004a; \4\ Page in litt. 2005.
In 2000, there were 976 breeding adult plovers observed in coastal
California. Surveyors observed 1,387 and 1,444 adult plovers during
similar breeding season surveys conducted in 2002 and 2003,
respectively. Statewide breeding season window surveys for California
demonstrate an increase in observed breeders from 2001 through 2005,
although there is still an overall decline when compared to historic
breeding population numbers (J. Baldwin, in litt. 2004; K. Lafferty, in
litt. 2002).
The increase in the number of adult plovers observed during
breeding season window surveys in the southern part of California is
related, at least in part, to protections and associated management
provided to the federally endangered California least tern (Sterna
antillarum browni) (Persons and Applegate 1996). Predator management,
habitat restoration, leash laws, controlled recreational vehicle use,
symbolic fencing, and other measures have contributed to the Statewide
increase in breeding Pacific Coast WSP and also provided benefits to
interior plovers wintering on the coast.
Baja California, Mexico--Occupancy of Sites and Number of Pacific
Coast WSP: Along the Pacific coast of Baja California, Mexico, most
plover nesting areas are associated with the largest wetlands. A survey
of breeding western snowy plovers along the Pacific coast of Baja
California between 1991 and 1992 found 1,344 adults, mostly at four
coastal wetland complexes: Bahia San Quintin, Lagunas Ojo de Liebre and
Guerrero Negro, Laguna San Ignacio, and Bahia Magdalena (Palacios et
al. 1994). Based on detection ratios established for surveys on the
United States Pacific coast, this indicated a coastal Baja population
of at least 1,900 adults (Palacios et al. 1994; Page et al. 1995a). We
have no information of any more recent estimates (E. Palacios, in litt.
2004).
Discussion of the Petition
The petition asserts that the Pacific Coast WSP does not meet the
Act's definition of a threatened species as its population is in flux
rather than decline. The petition offers a table and a graph to support
this assertion: The graph in section 5.1.2 of the petition provides
breeding population counts for Vandenberg Air Force Base (VAFB) for
1978 through 2001, and the table in section 5.1 (included as part of
Table 2 above) provides breeding population census counts for the
California coast during 6 years from 1980 to 2000. The graph shows VAFB
breeding population fluctuating in size from more than 100 to about 20
between 1978 and 2001.
The petition states that the VAFB data reflect dramatic
fluctuations that can occur within the plover population. Vandenberg
has two sections of beach that support plover breeding known as North
Beach and South Beach. The graph presented within the petition
(subsection 5.1.2) shows that Vandenberg's plover population has
fluctuated dramatically, with an overall increase from 119 birds in
1978 to 121 birds in 2001 (Surf Ocean Beach Commission 2002). However,
the petition does not provide the sources for the data in the graph. We
believe the data in the petition's graph from 1993 to 2001 are from
annual plover monitoring reports that VAFB started in 1993 (e.g.,
Persons 1994; Hickey and Page 2001) because we know of no other source
from which the information could have come.
It appears that the 1978 data in the petition's graph are from Page
and Stenzel (1981), but it is not clear upon what the intermittent
counts presented in the graph between 1978 and 1993 are based. This
graph shows a population increase from 193 to 239 breeding adults over
the years 1993 to 1997, a decrease to 132 and then 78 adults in 1998
and 1999 following severe storms and an oil spill in the winter of 1997
through 1998, and then a slow increase up to 122 adults in 2001. The
VAFB monitoring reports also note generally increasing efforts to
exclude human interference with nesting during these years. Based on
these data alone, it appears that plover breeding numbers can be
seriously affected by random natural events such as heavy storms, but
this does not support the petition's conclusion that the plover
population is in flux rather than decline. The 1978 data, which
petitioners offer as evidence of an overall increase of 119 to 121
birds, was itself collected after heavy winter storms. These storms
were so severe that only 7.1 mi (11.5 km) of beach were available for
nesting (Page and Stenzel 1981; L. Stenzel, pers. comm. 2003); in
contrast, in 2001, 12.5 linear miles (mi) [20.1 linear kilometers (km)]
of beach were available for nesting (Hickey and Page 2001). The 1978
numbers would therefore likely have been depressed from historic
levels, and would constitute poor support for the petition's
conclusions regarding overall population trends. More importantly, we
do not consider census data from VAFB alone to reasonably support
conclusions concerning the entire Pacific coast population. Pacific
Coast WSP do occasionally nest or renest at other coastal locations
(Stenzel et al. 1994; Page et al. 1995a), so fluctuations in the VAFB
breeding population could either be caused or moderated by
[[Page 20613]]
immigration to and emigration from other beaches.
The table in section 5.1 of the petition provides census data for
the California coast and serves as a better indication of population
trends for the Pacific Coast WSP, because ``the California coast
population represents at least 90 percent of the listed Pacific coast
population in the United States'' (D. Noda, in litt. 2001) (see table
1). Yet, the data presented in this petition table show a steady
decrease in population from 1980 to 2000 except for a particularly high
count in 1997 and a somewhat low count in 1995. The 1997 and 1995
surveys were both conducted differently than those for other years and
are therefore not directly comparable to other years. The 1995 census
did not include counts from several important breeding sites such as
South San Francisco Bay (P. Nieto, SRS Technologies, in litt. 2002; L.
Stenzel in litt. 2004a; G. Page, pers comm. 2003). The 1997 population
estimate is based on intensive monitoring information for some areas
combined with ``corrected'' window survey data from previous years for
other areas (Nur et al. 1999; G. Page, pers. comm. 2003). All other
population estimates in the petition's table in section 5.1 are totals
of window survey counts from the known breeding sites.
We developed Table 2 (above) to show California coastal population
estimates based on the observed number of adult plovers during breeding
season window surveys. Table 2 consists of the population counts
reported in the petition's table for years other than 1995 and 1997,
along with population counts from 2002 through 2005 which we added to
the Table.
The increase first observed in 2002 is encouraging, and we
attribute the population increases to the implementation of
conservation strategies by our recovery implementation stakeholders,
such as California State Parks, who have engaged in habitat restoration
and the use of extensive symbolic fencing. It is also important to note
that the population level documented by Page and Stenzel (1981), was
likely depressed by severe storms and resulting beach erosion during
the winter of 1977 through 1978 (Page and Stenzel 1981). Counts
conducted at VAFB from 1998 through 2000 showed a drop in adult plover
numbers from 238 to 132 following similarly severe storms during the
winter of 1997/1998 (Applegate and Schultz 1999; Applegate and Schultz
2000). Although the survey conducted in 1977 through 1980 provided
fairly high population estimates, Page and Stenzel (1981) noted:
``Numbers have definitely declined on the coast; the species was not
found breeding in 33 of the 53 locations with breeding records prior to
1970. Of the 33 areas, 28 are not likely to have regular breeding
populations again because the habitat has been destroyed or human use
of the area is too great.'' The petition interprets such conclusions as
speculative since they were not based on census data and do not show
how often particular breeding sites were used. While we agree that any
precise population estimates based on such data would be speculative,
we believe the indications of lost habitat provided by Page and Stenzel
(1981) are well supported and reasonably lead to the conclusion that
historic population levels were higher than those documented in the
1977 to 1980 census. We therefore consider the available data on the
coastal California population to provide more support for the
contention that the Pacific Coast WSP has declined from historical
levels.
The listing decision was also based on the loss of 33 California
breeding sites. An additional 11 sites have been subsequently
identified as having also lost nesting plovers since the original work
was completed and reported in the listing decision (L. Stenzel, in
litt. 2004b). Consequently, the loss of 44 of 53 breeding sites in
California represents an 83 percent reduction in historical nest
locations. Some of those sites in southern California were especially
significant. Places like Los Angeles County, where 25 miles of former
breeding habitat were lost, may have supported up to 600 pairs (1200
breeding birds) of plovers. The estimate is extrapolated from an egg
collector's 1903 record of 50 pairs along a 2 mile section of Manhattan
Beach (L. Stenzel, in litt. 2004b). At the time of the 1993 listing,
Oregon had lost 79 percent (23 of 29) of its historic nesting sites,
and Washington had lost 40 percent of its nesting locations (2 of 5)
(Service 1993 (58 FR 12864)). Additionally, the remaining habitat has
been degraded by the colonization of nonnative European beach grass by
occupying nesting substrate and changing from the open structure that
plovers prefer, increased number of predators, and increased human use.
Addressing the above three factors through effective management range-
wide and the reestablishment of 4 former breeding sites in Oregon (D.
Lauten, in litt. 2004) have bolstered plover populations since listing
(G. Page, in litt. 2004a).
The petition also cites a recent Pacific Coast WSP viability
analysis that indicates the population would likely remain above an
``extinction threshold'' of 50 individuals for at least 100 years under
the 1999 status quo (Nur et al. 1999). However, the petition did not
note that the ``status quo'' scenario (Scenario 1) assumed that
existing protections and management actions under the Act would
continue and projected a significant downward trend in population over
the next 100 years in the absence of additional efforts. Under a ``no
management'' scenario (Scenario 12), the analysis found a 51 percent
probability of reaching an extinction threshold after 100 years. The
analysis did not consider a scenario involving the complete removal of
protections under the Act. We therefore do not consider the petition's
statement that the Pacific Coast WSP population is healthy but in flux
to be well supported by available data, especially if protections under
the Act are removed.
Distinct Population Segment
In a 12-month finding, we must determine if: (1) The petitioned
action is warranted; (2) the petitioned action is not warranted; or (3)
the petitioned action is warranted but precluded by other higher
priority activities. Under the Act, a species is defined as including
any subspecies and any distinct population segment of a vertebrate
species (16 U.S.C. 1532). To implement the measures prescribed by the
Act and its Congressional guidance, we and the National Marine
Fisheries Service (National Oceanic and Atmospheric Administration-
Fisheries), developed a joint policy that addresses the recognition of
DPSs of vertebrate species for potential listing actions (Service and
NMFS 1996a (61 FR 4722)). The policy allows for a more refined
application of the Act that better reflects the biological needs of the
taxon being considered, and avoids the inclusion of entities that do
not require its protective measures. As noted above, in 1993, we listed
the Pacific Coast population of the WSP as threatened. As this was
prior to our 1996 DPS policy, a first step in this status review
process is to review the available information to assess whether the
Pacific Coast WSP 1993 listing determination is consistent with the
1996 DPS policy.
The DPS policy specifies that we are to use three elements to
assess whether a population segment under consideration for listing may
be recognized as a DPS: (1) The population segment's discreteness from
the remainder of the species to which it belongs; and (2) the
significance of the population segment to the species to which it
belongs; and (3) the population segment's conservation status in
relation to the ESA's standard for listing (61 FR
[[Page 20614]]
4722, 4725). If we determine that a population segment meets the
discreteness and significance standards, then the level of threat to
that population segment is evaluated based on the five listing factors
established by section 4(a) of the Act to determine whether listing the
DPS as either threatened or endangered is warranted. The DPS policy
also states: ``Listing, delisting, or reclassifying distinct vertebrate
population segments may allow the Services to protect and conserve
species and the ecosystems upon which they depend before large-scale
decline occurs that would necessitate listing a species or subspecies
throughout its entire range. This may allow protection and recovery of
declining organisms in a more timely and less costly manner, and on a
smaller scale than the more costly and extensive efforts that might be
needed to recover an entire species or subspecies'' (61 FR 4722, 4725).
Below, we address under our DPS policy the population segment of the
WSP currently listed as a DPS that occurs within 50 miles of the
Pacific coast in Oregon, Washington, California, and Mexico.
Discreteness
The DPS policy states that a vertebrate population segment may be
considered discrete if it satisfies either of the following two
conditions:
1. It is markedly separated from other populations of the same
taxon as a consequence of physical, physiological, ecological, or
behavioral factors. Quantitative measures of genetic or morphological
discontinuity may provide evidence of this separation; or
2. It is delimited by international governmental boundaries within
which differences in control of exploitation, management of habitat,
conservation status, or regulatory mechanisms exist that are
significant in light of section 4(a)(1)(D) of the Act.
The following discussion addresses only the first condition, since
the Pacific Coast WSP DPS includes plovers within Baja California,
Mexico and is not delimited by an international boundary.
The 1993 listing rule stated that the Pacific Coast WSP is
``genetically isolated'' from the interior breeding populations (58 FR
12864). We based this conclusion on banding and monitoring data, not
genetic data. At the time of listing, we assumed the reproductive
separation indicated by the banding data, over time, could lead to
genetic differentiation. Genetic data for the western snowy plover was
not available in 1993.
In this status review process, we examine the best information now
available, which includes banding, monitoring, and genetic information,
and assess the petition's additional points on discreteness, to
determine if the 1993 listing determination was consistent with the
1996 DPS policy. Western snowy plovers from populations in the eastern
interior (east of the Rockies), the Gulf Coast, and the Mexican
interior are not likely to interact with the Pacific Coast WSP, and are
not known to visit the Pacific coast (Page et al. 1995a). We thus focus
our discreteness analysis on the Western snowy plovers from populations
in the western interior (west of the Rockies), and the Pacific Coast
WSP.
Banding and Monitoring Information
Banding and monitoring studies are useful methods for evaluating
the discreteness of two populations provided that the banding effort
adequately samples each population, and the monitoring effort is
adequate to provide reasonable probabilities of detecting banded
individuals (J. Plissner, in litt. 2005). Several banding and
monitoring studies have been conducted that address the Pacific Coast
WSP (Spear 1979; Stenzel and Peaslee 1979; Henderson and Page 1979;
Widrig 1980; Page and Stenzel 1981; Page et al. 1983; Wilson-Jacobs and
Meslow 1984; Warriner et al. 1986; Herman et al. 1988; G. Page, in
litt. 1989; Page and Bruce 1989; Stern et al. 1990a, 1990b, 1991a,
1991b; Page et al. 1991; ODFW 1994; Palacios et al. 1994; Paton 1994;
Persons 1994, 1995; Stenzel et al. 1994; Page et al. 1995b; G. Page et
al., Point Reyes Bird Observatory (PRBO), in litt. 2002; Powell et al.
2002; C. Sandoval, in litt. 2002; G. Page, PRBO, in litt. 2004b; G.
Page, PRBO, in litt. 2005). Some of these studies were not specifically
designed for the purpose of evaluating the discreteness of the Pacific
Coast WSP, but nonetheless provide useful information for this
analysis.
In this finding, we rely primarily on the banding and resighting
efforts conducted during the period of 1984 through 1993, as this is
the period when banding efforts were underway at several areas on the
Pacific coast and in the western interior, and nest monitoring studies
and breeding season surveys were underway at many locations when banded
birds could be detected. Interior populations have not been banded
since 1993 (L. Stenzel, in litt. 2005). From 1984 through 1993, a total
of 4,170 plover chicks and breeding adults were banded at nine sites on
the Pacific coast (3,077 banded birds), and at four western interior
locations (1,093 banded birds) (G. Page, in litt. 2004b). The coastal
locations included sites in both Oregon and central California, while
the western interior locations included sites in Utah, Oregon, and
California.
Subsequent nest monitoring and breeding season surveys conducted in
the Pacific coast and western interior breeding zones from 1985 through
1995 provided an opportunity for resightings of banded birds. During
that time, a total of 22 U.S. coastal surveys; 1 coastal Baja
California, Mexico survey; and 4 western interior surveys were
conducted, many of which were repeated over several years (Palacios et
al. 1994; G. Page, in litt. 2004b). Collectively, these surveys covered
essentially the entire extent of U.S. coastal breeding habitat, as well
as extensive portions of western interior and Baja California, Mexico
coastal habitat, though not all such locations were surveyed every year
(Palacios et al. 1994). During this same time period, 10 U.S. coastal
and 4 western interior nesting studies were also conducted at sites
along the entire Oregon Coast, Utah, eastern Oregon, and numerous
locations on the California coast and interior (G. Page, in litt.
2004b). Nesting studies involve repeated searching and monitoring of
nests and nesting areas over the course of at least one breeding
season, and are more comprehensive than surveys.
A total of 907 banded plovers were detected by these breeding
surveys and studies. It is important to note that this figure does not
include plovers that were resighted in their original region (coastal
or western interior) without evidence of nesting, and does not include
plovers that were banded on the coast during the winter, as their
breeding range could not be established. The total does include six
plovers that were found nesting in more than one location, and so were
counted twice. Of these 907 resighted plovers, only 13 (1.4 percent)
were found in a geographic area (coastal or western interior) that was
different from their original breeding range. Two of those 13 plovers
(0.2 percent of the total 907 birds) were found nesting outside of
their original breeding range. One of these two plovers, a coastal
female nesting at the Kesterson National Wildlife Refuge in 1986, was
one of the two birds mentioned in the original listing rule (Service
1993 (58 FR 12864)). The other was a male banded in the interior
(though never found nesting in the western interior) and later found
nesting on the coast in 1995. The other 11 plovers were all coastally
banded and found in the interior without nests (G. Page, in litt.
2004b).
[[Page 20615]]
In addition to the 1984 through 1993 period, the period from 1977
through 1983 provides another opportunity to detect movements between
the western interior and Pacific Coast WSP populations. However,
surveys were less comprehensive during this time period, and only one
banding study took place in the western interior. Therefore, this
period is less useful for assessing breeding dispersal, but still
provides additional relevant information. During this period, 599
plovers were banded at seven sites along the central California coast,
and 400 were banded in the western interior at Mono Lake, California
(G. Page, in litt. 2004b). The coastal survey effort included seven
breeding season surveys across the U.S. range of the coastal
population, as well as seven nest monitoring studies from Marin to San
Luis Obispo Counties, California. The interior survey effort included
three breeding season surveys, as well as the ongoing banding studies
at Mono Lake (L. Stenzel, pers. comm. 2004). None of the plovers banded
at Mono Lake were observed on the coast during the breeding season. One
female, banded as a chick at Monterey Bay along the California coast,
was found nesting at Mono Lake in 1978. This was the first of the two
females mentioned in our original listing determination (Service 1993
(58 FR 12864)) as having bred outside the coastal population.
In addition to colored bands, whose combinations were administered
by the Point Reyes Bird Observatory (PRBO), some studies employed metal
bands administered by the Patuxent Bird Banding Lab. Resightings of
these bands were less common, since recapture of the bird is generally
required to read the band number. Of the 304 band retrievals reported
to Patuxent Bird Banding Lab for years 1969 to 2002, one male was found
to have moved from the Pacific coast to an interior location. This
plover was banded during the non-breeding season (November 1984) near
Ano Nuevo, California, and retrieved during the breeding season (June
1988) near Lake Albert, Oregon (G. Goldsmith, in litt. 2004). The
banding dates and associated migration suggest that the plover was an
interior bird overwintering on the California coast. The age of the
plover was unknown at the time of banding. There are no records in this
data set of plovers moving in the opposite direction, from the western
interior to Pacific coast.
Review of Banding Data
We asked six researchers familiar with avian banding studies to
examine the available banding data for the Pacific Coast WSP and
plovers from the interior west of the Rocky Mountains, and provide us
their professional opinions about the adequacy of those studies for
determining reproductive separation between the two populations. Four
of the reviewers responded. Three concluded that there appears to be
little exchange of reproductive individuals between the western
interior and coastal sites (G. Smith, USGS, in litt. 2004; B. Andres,
Service, in litt. 2005; J. Plissner, ABR Inc., in litt. 2005). However,
three of the reviewers (the fourth reviewer and two of the three
reviewers mentioned above) also noted that because monitoring in the
interior had been less comprehensive than on the coast, there is more
uncertainty about the ability to detect coastal plovers that may have
moved to the interior (B. Andres, in litt. 2005; C. Elphic, University
of Connecticut, in litt. 2005; J. Plissner, in litt. 2005). They felt
it was possible that a coastal breeding plover could move to the
interior undetected, but it was highly unlikely that an interior
breeding plover could move to the coast without being observed, as the
coastal resighting efforts were more extensive temporally and
geographically than those at interior sites. These three reviewers
stated that the available data are adequate to conclude that there is
little interaction between the breeding coastal and interior
populations. One reviewer noted dispersal between inland and coastal
populations may be episodic and associated with temporal variation in
breeding conditions at regional scales, and that the banding efforts
have not been extensive enough to address this possibility for the
range of conditions (J. Plissner, in litt. 2005).
Conclusion on Banding Data
We find that the existing banding and resighting data are
sufficient to document that the Pacific Coast WSP and the western
interior breeding populations experience limited or rare reproductive
interchange. We are most confident in the data from the 12-year period
1983 through 1995, as that is the period with the most extensive
banding studies and search efforts. The results from that period
indicate that 98.6 percent of the sampled plovers were observed during
the breeding season using the same breeding range as where they were
originally banded. We consider the results from that period sufficient
to document a marked separation of breeding ranges, and illustrate that
the amount of interchange between coastal and western interior
populations is likely to be extremely low, though not zero. Results
from the 1977 through 1984 period and the Patuxent banding data are
also consistent with this conclusion. Our DPS policy does not require
complete reproductive isolation, and allows for some limited
interchange among population segments considered to be discrete
(Service and NMFS 1996a (61 FR 4722)). Based on the results of these
banding and monitoring data, we conclude that the Pacific Coast WSP is
not freely interbreeding with other members of the taxon, although some
genetic interchange likely occurs at a very small rate. This
constitutes a marked separation due to breeding behavior.
The banding data also indicate that interior nesting plovers
overwintering on the Pacific coast are likely to be obligatory
migrants, whereas many individuals in the Pacific Coast WSP either do
not migrate, or do so only for short distances along the coast (Page et
al. 1995a). This behavioral difference tends to set Pacific Coast WSP
individuals apart from the interior birds with which they may mix
during the winter.
Additional Points on Discreteness
The petition asserts that the Pacific Coast WSP is not highly
isolated, and provides VAFB monitoring records from 1993 to 1999 as
supporting documentation to demonstrate that the Pacific Coast WSP and
western interior populations commonly interbreed. VAFB is a coastal
Santa Barbara County breeding site. The petition contains a table
summarizing the VAFB survey records and indicating that during 1993 to
1999, 90 plovers present during the breeding season had hatched
elsewhere. However, our analysis below of the VAFB monitoring records
supports a different conclusion than that reached by the petitioners
and instead provides additional evidence demonstrating that coastal and
interior populations do not commonly interbreed.
Two of the 90 non-local birds cited in the VAFB monitoring records
came from the western interior. These two plovers were banded at Abert
Lake (in interior Oregon) (Stern et al. 1990a) during the 1988 through
1989 banding season and were sighted at VAFB (on the California coast)
on July 29, and August 19, 1993, during the breeding season (Persons
1994). However, as noted by Persons (1994), post-breeding migration of
plovers typically begins in early July, so only late June censuses
accurately reflect the size of the breeding population. Later censuses
include many non-breeding plovers. Stenzel et al. (1994) also report
that after the first few days of July, plovers that move into a
breeding area do not nest in the area. Therefore, sightings made only
after the
[[Page 20616]]
first week in July, unless supported by evidence of breeding, are not
good evidence of population interchange.
The other 88 plovers in the VAFB monitoring records had all hatched
on the coast, and were, therefore, also members of the coastal
population (Stenzel et al. 1994). Such data tend to support our
determination that the Pacific Coast WSP is discrete, as these data
show that coastal population members tend to interbreed among
themselves rather than with interior birds. These results are also
consistent with additional studies, which found western snowy plovers
renesting in new locations after having either lost or successfully
fledged their first clutch (Warriner et al. 1986; Stenzel et al. 1994).
For the Pacific Coast WSP, it is also common for one partner, usually
the female, to abandon a brood between hatching and fledging and to
start a new clutch in a new location with a new partner. Distances
traveled to new nesting locations range from meters to hundreds of
kilometers (Warriner et al. 1986; Stenzel et al. 1994). However, no
such mid-season location changes have been shown to result in nesting
at both coastal and interior sites.
Genetics
Evidence of genetic distinctness can inform our analysis of the
discreteness of a population. In determining whether the test for
discreteness has been met under our DPS policy, we consider available
genetic evidence, but such evidence is not required to recognize a DPS.
The petition questions the validity and effectiveness of using banding
studies, as compared to genetics, for investigating levels of gene
flow. When conducted properly, we find that both banding and genetics
studies provide useful information. The petition relies heavily on a
master's thesis (Gorman 2000) that did not find evidence of genetic
differentiation between the Pacific Coast WSP and western interior
snowy plover populations using mitochondrial DNA (mt DNA).
Several commenters also pointed out that mtDNA markers in Gorman's
study may have been indicating interbreeding that happened thousands of
years ago and suggested that additional studies using a marker with a
finer resolution, such as microsatellite comparisons, should be
conducted (B. Crespi, in litt. 2002; J. Neigel, in litt. 2004; B.
Foster, in litt. 2004; L. Gorman, in litt. 2004). In fact, a more
recent study by Funk et al. (2006) includes analysis of microsatellite
DNA markers. Funk et al. (2006) found no statistically significant
genetic differentiation between Pacific Coast WSP and western interior
snowy plover populations using mtDNA and microsatellite DNA markers.
Given these available data indicating that the mtDNA and
microsatellite data show no evidence of significant genetic
differentiation between Pacific Coast and interior WSP populations, the
Service's responsibility is to interpret the result in terms of our DPS
policy. As noted in Funk et al. (2006), ``only a few dispersers per
generation are necessary to homogenize gene pools between breeding
habitats (Wright 1931; Slatkin 1985, 1987; Mills and Allendorf 1996).''
Therefore, failure to identify genetic differences between Pacific
Coast and western interior plovers does not necessarily mean that there
is a large amount of movement between the two areas. Movement of just a
few individuals may prevent genetic differentiation, but movement of a
few individuals may not be sufficient to maintain significant
demographic connectivity (Funk et al. 2006).
Thus, the two regions (in this case, the Pacific Coast and western
interior populations) may continue to function as demographically
independent populations despite sufficient gene flow to homogenize gene
pools (which may require just a few individuals per generation) (Funk
et al. 2006). That the two may be demographically independent, as noted
by Funk et al. (2006), is particularly likely given that they have
unique habitats (e.g., Pacific Coast birds tend to occur, with some
exceptions, on open sandy beaches adjacent to the Pacific Ocean, while
Great Basin birds occur on sand/salt flats on alkali lakes of the Great
Basin (Page et al. 1995), low dispersal rates (Page, in litt. 2004a),
and population declines (Page et al. 1991). Funk et al. (2006) suggest,
for example, that ``if a Pacific Coast population of snowy plovers went
extinct, a few immigrants from the Great Basin [interior] may not be
sufficient to recolonize the empty habitat patch.'' They further
suggest that empty patches of Pacific Coast habitat are not currently
being recolonized in this fashion and that there is no reason to expect
they would be recolonized in the future when habitat is even further
fragmented.
In summary, the genetic information available to us in Gorman
(2000) and Funk et al. (2006) shows no evidence of genetic
differentiation between Pacific Coast and western interior WSP, using
mtDNA and microsatellite markers. For this reason, we do not find that
the genetics data currently available to us provide evidence that
Pacific Coast WSP is ``markedly separated'' from western interior
populations of WSP. However, as outlined above and articulated in Funk
et al. (2006), it is reasonable to conclude that other data (i.e.,
besides genetic data) are relevant to an analysis of whether WSP from
these two geographic regions can be considered ``markedly separated''
(i.e., discrete) per our DPS policy. As noted above in the Banding and
Monitoring Information section, we believe there is substantial
evidence from banding data to indicate that exchange of individuals
between the Pacific Coast and western interior regions is minimal.
Conclusion on Discreteness
Based on the available information in the petition, scientific
literature, and in our files regarding western snowy plover range and
distribution, we conclude that the Pacific Coast WSP is markedly
separate from other populations of the subspecies due to behavioral
differences and that it, therefore, meets the requirements of our DPS
policy for discreteness. Banding studies and resighting efforts
demonstrate that during breeding, the Pacific Coast WSP segregates
geographically from other members of the subspecies, even those that
also winter on the Pacific coast. Although not absolute, this
segregation is marked and significant.
Significance
Under our DPS policy (61 FR 4722), once we have determined that a
population segment is discrete, we consider its biological and
ecological significance to the larger taxon to which it belongs. This
consideration may include, but is not limited to, the following
factors:
1. Persistence of the discrete population segment in an ecological
setting unusual or unique for the taxon,
2. Evidence that loss of the discrete population segment would
result in a significant gap in the range of the taxon,
3. Evidence that the discrete population segment represents the
only surviving natural occurrence of a taxon that may be more abundant
elsewhere as an introduced population outside its historic range, or
4. Evidence that the discrete population segment differs markedly
from other populations of the species in its genetic characteristics.
We evaluated available information to assess whether the 1993
designation was consistent with the above factors or other relevant
factors to explain why the Pacific Coast WSP is significant to the
subspecies of western snowy plover. In this finding, we are only
addressing the significant gap in the range of the taxon because that
is the only significant criteria factor that applies.
[[Page 20617]]
Significant Gap in the Range of the Taxon
One approach to assessing whether the Pacific Coast WSP constitutes
a substantial portion of the western snowy plover subspecies (Pacific
Coast, interior, and Gulf Coast) is to evaluate the size of the
subspecies. Estimating size of a broadly yet patchily distributed
subspecies like the western snowy plover is a difficult task to
accomplish (Gorman and Haig 2002). At this time, our best available
estimate of the subspecies' current total size is about 24,136 birds
(Page et al. 1995a; P. Paton, University of Rhode Island, in litt.
2004; Zdravkovic 2004; Gorman and Haig 2002; L. Kelly in litt. 2006; M.
Jensen in litt. 2006; G. Page in litt. 2005) (see Table 1).
The estimate in Table 1 of the total number of birds of the
subspecies takes into account the following new data: Dr. Peter Paton
recently revised his original published estimate of 10,600 birds for
Utah (Page et al. 1995a) to 4,189 birds (P. Paton, in litt. 2004).
Stenzel provides information that the 4,478 figure used to describe the
Pacific Coast WSP population through the 2004 breeding season is likely
an underestimate due to some areas in southern California not being
surveyed (L. Stenzel, in litt. 2004a). The new observed estimated
number of birds (3,695) is based on the 2005 breeding season (see Table
1 above), which is approximately a 3 percent drop from Stenzel's 2004
figure. Additionally, researchers in Texas believe that as many as
1,000 plovers nested along the Texas Gulf coast in 2004, a substantial
increase from the 100 reported by Page et al. (1995a) (Zdravkovic
2004). We are not aware of what effect, if any, the 2005 hurricanes may
have had on the Gulf coast plovers and their habitat.
Monitoring results are not available for the interior and northeast
coastal Mexico areas, and recent estimates have not been developed for
several of the interior western snowy plover breeding areas. In light
of this inconsistent survey coverage, we considered it appropriate to
use the largest of the available estimate ranges available for the
interior breeding plovers, so as not to overstate the significance of
the Pacific Coast WSP. We acknowledge that the number of birds within
the subspecies could be more or less than that indicated by the best
available information. As presented in Table 1 above, the Pacific Coast
WSP current population estimate is approximately 20 percent of the
taxon's total estimated size (4,804 of 24,136 total birds). Therefore,
we contend that using this conservative interpretation of the best
available data, the 2005 Pacific Coast WSP constitutes approximately 20
percent of the subspecies.
The petition also states that because the range of interior western
snowy plovers overlaps that of Pacific Coast WSP (by virtue of sharing
winter ranges), they have ``ample opportunity to socialize, pair bond,
and inter-breed.'' We agree that the potential exists for interactions
to occur between wintering interior western snowy plovers and Pacific
Coast WSP, but banding data indicate that such interactions occur at
very low rates.
The petition suggests, without any supporting evidence, that
interior-nesting western snowy plovers would colonize the coastal
breeding habitat if the Pacific Coast WSP were extirpated. As described
earlier, the Pacific Coast WSP population declined during the 1970s to
mid-1990s, leaving many historical breeding locations vacant throughout
the coastal range, and even though ample habitat remained intact, it
was not colonized by any plovers (coastal or interior). Analysis of the
available banding data indicates that there is little interchange
between the coastal and interior breeding populations (G. Smith, USGS,
in litt. 2004; B. Andres, Service, in litt. 2005; J. Plissner, ABR
Inc., in litt. 2005). Although low levels of breeding dispersal from
the coast to the interior remain a possibility, the banding studies
provide a high degree of confidence that any such dispersal is out of
the coastal population, and not into it (C. Elphic, in litt. 2005).
This is consistent with additional analysis indicating that the
available banding data are adequate to conclude that an insignificant
number of individual plovers disperse from interior breeding sites to
coastal breeding sites (J. Plissner, in litt. 2005), and it is unlikely
that interior breeding plovers would disperse to coastal breeding sites
(B. Andres, in litt. 2005). We have no data documenting interior birds
colonizing vacant coastal areas.
This apparent lack of interchange between coastal and western
interior breeding sites may be explained by the relatively high degree
of site fidelity exhibited by this species. Breeding and winter site
faithfulness vary between sites. Stenzel et al. (1994) report that
plovers were faithful to their known breeding location in northern-
central coastal California about 59 percent of the time for females and
84 percent of the time for males. Partial-absence (missing for a
portion of the breeding season) from known breeding locations was more
common than complete absence. Of the 147 birds observed moving during
the breeding season, 25 females and 14 males moved from 50 to 708 miles
(31 to 1,140 kilometers). All 147 birds remained within the coastal
zone, either north or south of their previously known breeding
location. There was no evidence of pair movements, only movements for
individual plovers. Page et al. (1995a) present the following adult
plover resighting rates at breeding locations between consecutive
years: Monterey Bay, California, males 76.8 percent, females 65.8
percent (Warriner et al. 1986); Mono Lake, California, males 77.8
percent, females 44.9 percent (Page et al. 1983); Lake Abert, Oregon,
males 64.1 percent, females 40.9 percent (Stern et al. 1990a). There is
also evidence of fidelity to wintering areas. About two-thirds of
plovers banded during the breeding season at Lake Abert, Oregon, were
located on their coastal California or Baja California, Mexico,
wintering areas for 2 subsequent years, and about one-third were
subsequently located at least 3 years following banding (Page et al.
1995b).
There is no evidence to indicate western interior populations would
recolonize the Pacific coast if the listed population were lost.
Therefore, such loss would remove 2,000 miles of coastline, stretching
from Washington to Baja California, from the subspecies' breeding
range. The Pacific coast constitutes the vast majority of coastal
breeding habitat used by the subspecies (the rest being in southern
Texas and northeastern Mexico), as well as the westernmost extent of
the taxon's breeding range.
We find that the Pacific Coast DPS is significant to the subspecies
of western snowy plover because it comprises approximately 20 percent
(one-fifth) of the subspecies' estimated population based on the 2005
breeding window survey results. We conclude that the best available
data demonstrate that the likelihood of pair bonding and interbreeding
between the Pacific Coast WSP and the interior-nesting western snowy
plovers is very low, and that there is no evidence indicating that
interior breeding plovers would rapidly reestablish a viable breeding
population along the Pacific Coast following the extirpation of the
coastal population. Accordingly, loss of the Pacific Coast WSP would
result in a significant gap in the breeding range of the taxon. It
would constitute the loss of a substantial percentage of the
subspecies, curtailing the taxon's current breeding range by 2,000
miles of coast line.
[[Page 20618]]
DPS Status--Conclusion
We find that the Pacific Coast WSP qualifies as a DPS under the
Act, as recognized under our 1996 DPS Policy (Service and NMFS 1996a
(61 FR 4722)). The Pacific coast population is discrete based on
extensive banding data showing marked reproductive separation from
other populations. Of the 4,170 plovers banded over the 12-year period
with the most extensive banding and resighting surveys, 907 were
resighted. Of these 907, 894 plovers (98.6 percent) were resighted
within their natal or nesting site breeding ranges, 11 coastal plovers
(1.2 percent) were resighted in the interior without nests, and 2
plovers (0.2 percent) were resighted nesting outside of their original
breeding range. These results suggest a marked reproductive separation
between the Pacific Coast WSP and other interior western snowy plovers.
The 1993 listing decision suggested that genetic differentiation
between coastal and interior populations was likely. There is no
evidence that such differentiation exists and existing information
suggests coastal and interim populations do not markedly differ
genetically. However, the banding data and the resighting efforts
provide compelling information that during breeding, the Pacific Coast
WSP segregates geographically from other members of the subspecies,
even those that winter on the coast.
The Pacific Coast WSP is also significant to the rest of the taxon
because its loss would cause a significant gap in the range of the
subspecies. The Pacific Coast WSP comprises approximately 20 percent of
the subspecies estimated total size. We have no evidence that interior
breeding plovers would reestablish a viable population along the
Pacific coast following the extirpation of the coastal population.
Accordingly, loss of the Pacific Coast WSP would result in a
significant gap in the breeding range of the taxon.
Conservation Status
When considering an action for listing, delisting, or reclassifying
a species, we are required to determine whether a species is endangered
or threatened based on one or more of the five listing factors
identified in section 4(a)(1) of the Act. These factors are: (A) The
present or threatened destruction, modification, or curtailment of its
habitat or range; (B) over utilization for commercial, recreational,
scientific, or educational purposes; (C) disease or predation; (D) the
inadequacy of existing regulatory mechanisms; and (E) other natural or
manmade factors affecting the continued existence of the species.
Delisting a species must be supported by the best scientific and
commercial data available. Delisting may occur only if such data
substantiates that the species is neither endangered nor threatened for
one or more of the following reasons: (1) The species is considered
extinct; (2) the species is considered to be recovered; and/or (3) the
original data available when the species was listed, or the
interpretation of such data, were in error (50 CFR 424.11).
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
The petition states that the ``western snowy plover has been very
adaptive at exploiting opportunities to breed at new habitat that was
created by humans including the Salton Sea, San Francisco Bay Salt
Ponds, Central Valley agricultural ponds, and Batiquitos Lagoon.'' We
agree with the petition's assessment as it relates to the Pacific Coast
WSP. The western snowy plover is an early successional species that
depends on dynamic habitat. As conditions change, the western snowy
plover (including the Pacific Coast WSP) has the ability to colonize
new sites. Because coastal habitats are dynamic, and change within a
season or between seasons, the Pacific Coast WSP must adjust. However,
our information shows that loss of nesting and wintering habitat
remains one of the primary threats to the Pacific Coast WSP throughout
its range. Causes of habitat loss include industrial and residential
development, the spread of nonnative dune-stabilizing vegetation, human
recreational use at levels that preclude nesting attempts, and various
habitat alteration projects.
Urban development permanently removes important nesting habitat
above the high tide line. It is a major source of habitat loss in all
three western U.S. coastal States, and particularly in southern and
central California (Page and Stenzel 1981; Page et al. 1995a).
Development may also affect beach accretion processes by removing areas
in which sand normally accumulates. Other secondary effects include
increases in human use of nearby beach areas (as with piping plover,
Service 1996), and increased predation of eggs and chicks in some areas
(see Predation section below). The Pacific coast is one of the fastest
growing regions within the United States (Crossett et al. 2004).
Another major source of habitat loss has been the spread of
nonnative dune-stabilizing vegetation such as European beachgrass
(Ammophila arenaria), which removes dune habitat by covering and
anchoring dunes and preventing the free movement of wind-blown sand.
Such grasses also provide cover for predators (Pickart 1997; Stern et
al. 1991b). European beachgrass was introduced to the Pacific coast in
the late 1890s as a means of stabilizing dunes to encourage
development. A secondary effect of dune stabilization has been human
development of beaches and surrounding areas (ODFW 1994). European
beachgrass has since spread along the Pacific coast from British
Columbia to Ventura County, California, invading every major dune
system in the plover's range from Santa Barbara County north (Pickart
1997). It is considered one of the primary causes of plover population
decline in Oregon (Oregon Parks and Recreation 2003). Once established,
it is extremely difficult and expensive to remove (Pickart 1997).
American beachgrass (Ammophila brevigulata), which is native to the
east coast and Great Lakes regions of North America, behaves similarly
to European beachgrass and has become the dominant introduced
beachgrass along much of the Washington coast (Washington Department of
Fish and Wildlife 1995). In southern California, giant reed (Arundo
donax) and South African iceplant (Carpobrotus edulis) have overgrown
plover habitat in some areas.
In southern California, large expanses of beach previously used for
nesting are no longer available as habitat due to extensive
recreational use by humans. Popular recreational beaches may be
completely covered by human footprints, and may also undergo daily or
weekly mechanized beach raking to remove trash and tide-cast wrack
(Page and Stenzel 1981; Powell et al. 2002). Although the removal of
trash is beneficial to plovers (see Predation section below), natural
tide-cast wrack such as seaweed provides important habitat for plover
prey populations such as flies and other invertebrates (Dugan et al.
2000; 2003). Beach raking may also flush adults from nests and crush
plover clutches, depending on the frequency of raking. Dugan et al.
(2003) state that up to 99.4 miles (160 kilometers) of sand beach
habitat south of Point Conception, California, are raked annually
during the Pacific Coast WSP nesting season.
The final category of habitat loss is habitat alteration projects,
which include diversions and impoundments of streams and rivers,
management of salt ponds for marsh habitat, dredging
[[Page 20619]]
and sand mining, and inappropriately designed breakwaters or beach
nourishment projects. Waterway diversion and impoundment activities,
such as the construction of seawalls and use of rip rap, can limit the
delivery of sand and thereby lessen the extent of beach habitat. In
southern California, blockage of lagoon mouths for road construction
has prevented tidal flushing and associated salt pan formation, thereby
eliminating important nesting habitat (Powell et al. 2002). Stream
stabilization projects can interfere with the natural shifting of river
mouths across the landscape, thereby allowing beachgrass (Ammophila
spp.) and other vegetation to take root (Powell et al. 2002).
Salt ponds, such as in the San Francisco, Monterey, and San Diego
Bays in California, may be operated to the benefit or detriment of
nesting plovers by allowing ponds to flood or dry at particular times
(Page et al. 2003). In the San Francisco Bay, salt ponds that are
managed for tidal marsh species, such as the salt marsh harvest mouse
(Reithrodontomys raviventris) and California clapper rail (Rallus
longirostris obsoletus), do not provide habitat for the plover (V.
Bloom in litt. 2005). We are working with the California Department of
Fish and Game and local landowners to develop a management plan for the
area, which will best meet the needs of all the listed species in the
area (M. Kolar, in litt. 2004).
A survey of breeding plovers in Baja California, Mexico, noted two
large salt works (one completed and one planned) at Laguna Oja de
Liebre and Laguna San Ignacia, respectively. The survey noted numerous
plovers continuing to nest at the completed facility, but also noted
the loss of some nests and chicks there due to vehicular use of the
area. The survey was unable to determine whether overall impacts from
the two facilities would be detrimental or beneficial (Palacios et al.
1994).
Sand mining by heavy machinery, such as at Monterey Bay,
California, eliminates nesting habitat within the area subject to
mining, degrades nearby habitat by removing replenishing sand, and
disturbs adjacent nesting due to noise and vehicle traffic (Guinon
1988). Dredging can disturb nesting plovers, alter natural patterns of
sand deposition, and encourage boat-related recreational activity in
plover nesting areas. Alternatively, dredge tailings have served as
important nesting habitat in Coos Bay, Oregon (Wilson-Jacobs and Dorsey
1985). Breakwaters and beach nourishment projects also have the
potential to benefit habitat by causing sand to accrete in nesting
areas, but if designed incorrectly can also erode nesting areas or
increase the slope of the beach and encourage invasive plants (Service
2001).
The petition offers some brief analyses of some of the threats to
the Pacific Coast WSP addressed by the listing rule. The petition
points out that many Pacific Coast WSP now breed in human created
habitat ``including the Salton Sea, San Francisco Bay Salt Ponds,
Central Valley agricultural ponds, and Batiquitos Lagoon.'' However,
the Salton Sea and Central Valley agricultural ponds are outside of the
breeding range of the coastal population (Service 1993 (58 FR 12864)).
Use of Batiquitos Lagoon as a breeding site has increased by a total of
14 birds since its restoration as a tidal marsh in 1996 (Port of Los
Angeles 2003; L. Stenzel, in litt. 2004a). The San Francisco Bay Salt
Ponds constitute genuine new, human-created habitat. In contrast to
this addition, the species has lost 44 of its 53 known historical
nesting sites in California prior to listing (Page and Stenzel 1981; L.
Stenzel, in litt. 2004b), 2 of its 5 nesting locations in Washington,
and 19 of its 29 nesting locations in Oregon (L. Stenzel, in litt.
2004b). Based on the best available data, we believe the loss of
habitat remains a significant threat to the population and the addition
of nesting habitat at the San Francisco Bay Salt Ponds does not offset
the full impact of this loss.
In summary, habitat loss that negatively impacts Pacific Coast WSP
has occurred in the past and continues to occur in the form of
development, spread of nonnative dune-stabilizing vegetation, human
recreational use at levels precluding nesting attempts, and habitat
alteration projects. While some nesting habitat has been added at San
Francisco Bay Salt Ponds that has benefited Pacific Coast WSP, it has
not been sufficient to offset past and ongoing habitat losses.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
The petition did not provide any information about this threat.
The only threat to Pacific Coast WSP from overutilization is
potentially from scientific research. Currently, we issue permits under
10(a)(1)(A) of the ESA to qualified individuals for nesting studies,
surveys, banding, and protective management techniques such as nest
exclosures. Disturbance of plovers is kept to a minimum through
surveyor training and by minimizing time spent in nesting areas. While
exclosures typically increase fledge rate, they also reveal nest site
locations to predators, thereby potentially increasing the danger to
adults and chicks as they leave the nest site to forage (Neuman et al.
in press). Accordingly, effects of exclosures should always be closely
monitored. Bands may occasionally result in leg injuries, including
foot loss, possibly due to abrasion and subsequent swelling (Page in
litt. 2005a). The percentage and severity of bandings resulting in
injuries is not currently known, but is likely to be low based on
numerous sightings of uninjured banded birds. Despite the low risk of
injuries, banding remains the best technique to study population
variables such as survival, recruitment, and dispersal, and appears to
be the most effective way to monitor populations and determine the
effectiveness of management strategies (Nur et al. 1999). We are
monitoring banding injuries through our Section 10(a)(1)(A) recovery
permit program, and have initiated an experimental program in the
Monterey Bay area to determine if band position on the leg can decrease
injuries by reducing the metal band's contact with sand. Sand wear on
the metal band may cause the band's edge to become sharp, contributing
to plover leg injuries. Additionally, sand grains can become lodged
between the metal band and the plover's leg, resulting in irritation of
the leg. We do not have any indication that leg injuries in plovers are
occurring as a result of using plastic colored bands, which are
flexible.
As noted in the petition, it is also theoretically possible for
bands to increase the likelihood of predation, by increasing the
visibility of the plovers. This is extremely difficult to test because
there is no way of knowing the predation rate on unbanded birds. If
such an effect does exist it would be more likely to apply to avian
predators, since the primary mammalian predators (red fox (Vulpes
vulpes) and coyote (Canis latrans)) tend to hunt in the evening and
night. Plovers depend on their cryptic coloration and behavior to
remain undetected by avian predators. Typically, plovers will crouch,
flattening their profile to approaching aerial predators. Consequently,
colored leg bands are covered by the crouching bird, making the bands
largely undetectable to predators until the plover is forced to flush.
The petition also notes that surveys and banding studies conducted at
VAFB from 1995 to 2000 did not find birds banded at VAFB that were more
than 3 years old; however, the study period was too short to find older
birds except during 1999 and 2000. Several older birds that
[[Page 20620]]
hatched at VAFB were found during surveys in coastal California in
2002, including 1 seven year-old, 2 six year-olds, 10 five year-olds,
and 21 three or four-year olds (P. Nieto, SRS Technologies, in litt.
2002). Most of these birds were found outside Vandenberg AFB, yet all
were found within the coastal population. In summary, we conclude that
overutilization is not a significant threat to the Pacific Coast WSP
because research and monitoring are conditioned through our Recovery
Permit program to reduce impacts, and steps have been taken to monitor
and reduce band-related injuries.
C. Disease or Predation
The petition did not provide any information about disease as a
threat. However our information shows that West Nile virus, a mosquito-
transmitted pathogen that can infect numerous species of birds,
reptiles, and mammals, has killed birds of various species in every
coastal California county (USGS 2005a), as well as one coastal county
in Oregon (Lane County) (USGS 2005b). The disease has not yet been
reported in any Washington coastal counties (USGS 2005c), but will
likely reach those counties in the near future, as it has spread
rapidly across the United States from an initial introduction in New
England (National Audubon Society 2004). The deadliness of the disease
to birds varies by species (National Audubon Society 2003), but the
disease has been identified in dead piping plovers (Charadrius
melodius) and killdeer (C. vociferus), both closely related to snowy
plovers (CDC 2004).
Clark in litt. (2006) reported that 26 adult plovers either died or
were found sick from the international boundary with Mexico to North
Island Naval Air Station in San Diego Bay during the period of January
through June, 2005. Although the cause of death remains uncertain,
researchers believe an unknown toxin may be the cause. Tests have not
identified the cause of sickness. We do not know if the illness extends
within the Mexican portion of the Pacific Coast WSP. There is also a
potential that ``Bird Flu'' (influenza) could also affect snowy plovers
and other wildfowl, although Bird Flu has not been documented in the
United States.
The petition raised the issue of predation in both an historical
and contemporary context. Specifically, the petition maintains that
humans have been altering predator populations in California since the
1700s when Spanish explorers began their movements along the Pacific
Coast. Because predators have been removed from western snowy plover
habitat, the petitioners believe that the plovers were able to
``colonize areas where they had never lived before.''
Predation has been found to be a major factor affecting nesting
success across the range of the DPS. In San Diego County, California,
crows (Corvus brachyrhynchos), ravens (C. corax), coyotes, and possibly
Argentine ants (Iridomyrmex humilis) were the primary causes of nest
failure in 1994, 1996, and 1997 (tidal flooding caused greater nest
loss in 1995) (Powell et al. 2002). In Monterey County, nonnative red
fox caused an increased number of nest failures from 1984 to 1991,
while avian predators including shrikes (Lanius ludovicianus) and
kestrels (Falco sparverius) had significant impacts on fledging success
from 1996 to 1999 (Neuman et al., in press). A study of Oregon beaches
identified predation by crows and ravens as the primary cause of nest
loss in 1978 and 1979 (Wilson-Jacobs and Meslow 1984); while red fox,
crows, and ravens caused low fledgling success rates across coastal
Oregon from 1990 to 2003 (D. Lauten et al., in litt. 2004). Additional
major predators include skunks (Mephitis mephitis) (Stern 1990b),
merlins (Falco columbarius), northern harriers (Circus cyancus) (Page
et al. 1997), dogs (Canis lupus), and cats (Felis cattus) (B. Farner
pers. comm. in Powell and Collier 1994; Page 1988).
Factors affecting predation levels on the Pacific Coast WSP include
trash left near nesting areas; the availability of nearby cover for
mammals or perches for birds; the existence of dependable food sources
such as dumps and fish cleaning sites for gulls, ravens, crows, or red
foxes; and the proximity of urban areas supporting dogs and cats
(Service 2001). Plovers spend so much energy reacting to human
disturbance that their ability to react appropriately to actual
predators is lessened (Powell et al. 2002), either due to acclimation
(Page et al. 1977) or stress and loss of foraging opportunities (Ruhlen
et al. 2003).
The petition asserts that humans may have helped plover populations
by killing many plover predators. Intensive management and control of
predators has likely led to an increase in plover numbers since the DPS
was listed. The use of nest exclosures has increased hatch rates
(Colwell et al. 2005; Lauten in litt. 2004; Fancher et al. in litt.,
2005), and the removal of predators at selected sites has improved
fledging rates (Lauten, et al. 2006). However, predation still impacts
reproductive success at numerous nesting locations (Persons and
Applegate 1997; Colwell et al. 2005) and therefore remains a threat to
the Pacific Coast WSP.
In summary, disease and predation impact site-specific plover
reproductive success and survival. Disease has become a recent, ongoing
threat since the 1993 listing, resulting in the death of plovers from
Monterey Bay, California, south to the Mexican border. We do not know
the extent of the mortalities in the United States because not all of
the carcasses are found due to predation, wind blown sand, and tidal
action. In addition, we do not have information regarding the extent of
plover deaths related to disease or toxins in Mexico. Deaths in the
United States will continue to be monitored, and funding has been
appropriated to help determine the cause of death. Predation continues
to be a major factor affecting nesting success, and thus constitutes a
threat to the Pacific Coast WSP. Management actions implemented largely
in response to the listing have controlled many factors affecting
predation. For example, the use of nest exclosures has significantly
increased nest hatch rates by reducing predation (Colwell et al. 2005;
Fancher et al. in litt., 2005), and predator management improves
fledging success and reproductive rates (Lauten et al. 2006). Current
site specific predator management has reduced the significance of
predation to the Pacific Coast WSP; however, if management actions are
no longer implemented, plover populations would likely drop at several
locations, possibly affecting population viability within key areas or
on the rangewide scale.
D. The Inadequacy of Existing Regulatory Mechanisms
The petition did not provide any information about this threat. Our
information is discussed below.
Federal Laws
United States
Since the species is currently listed under the Endangered Species
Act of 1973, as amended (16 U.S.C. 1531 et seq.), this law is the
primary mechanism for protecting the Pacific Coast WSP. Multiple
sections of the Act contain provisions that promote conservation of
listed species. Section 2(c)(1) states the policy of Congress that all
Federal agencies shall seek to conserve listed species and utilize
their authorities to further purposes of the Act. Section 4 outlines:
The threat factors for which a species can be listed; the formation of
recovery teams and development of recovery plans to address those
threats; reclassifications and delisting, and post
[[Page 20621]]
delisting monitoring requirements; and protective regulations (special
rules) for threatened species. Section 5 discusses conservation of
listed species through land and water acquisition. Section 6 calls for
cooperation with the States by entering into management and cooperative
agreements, and providing funding to those States with cooperative
agreements. Section 7 requires Federal agencies to carry out programs
to conserve listed species and to consult with the Service to ensure
that their actions do not jeopardize the continued existence of listed
species. Section 9 makes it unlawful to import, export, take, or
violate any regulation pertaining to listed wildlife, and on Federal
lands, plants. Section 10 authorizes: Scientific permits for research
or to enhance the survival and recovery of listed species; incidental
take permits based on a habitat conservation plan that will not
appreciably reduce the likelihood of survival and recovery of the
listed species; and experimental populations outside a species' current
range. Section 11 assesses civil and criminal penalties for violations
of the Act or its implementing regulations. These provisions are
applicable to the protection of a species while it is on the Federal
List of Endangered and Threatened Wildlife and Plants. If removed from
the list, the Pacific Coast WSP would no longer receive the protections
of listing or from the designation of critical habitat. Federal
agencies would no longer consult with us concerning the impacts of
actions that may affect Pacific Coast WSP to ensure that such actions
do not jeopardize the continued existence of Pacific Coast WSP, nor
would individuals seek section 10(a)(1) permits for private actions
affecting the species. It is possible that, in the absence of the
Federal listing, many state/local regulations and programs that
currently protect the Pacific Coast WSP would be repealed and
dismantled.
The Migratory Bird Treaty Act (MBTA) (16 U.S.C. 703 et seq.),
protects Pacific Coast WSP, and their eggs and nests, from being
killed, taken, captured, or pursued. However, it does not protect
habitat except to the extent that habitat alterations would directly
kill birds.
The Clean Water Act (CWA) (33 U.S.C. 1251 et seq.) prohibits
unpermitted discharge of pollutants (including dredge and fill
material) into ``the waters of the United States'' (33 U.S.C. 1311,
1362), including most rivers, streams, wetlands, and the ocean below
high tide (33 U.S.C 1362; 33 CFR 328.3, 328.4). The CWA affects
numerous potential threats to Pacific Coast WSP, including dredging and
most sand-mining operations, construction of jetties and breakwaters,
beach nourishment projects, oil and contaminant spills, sewage
discharge, construction in many ephemeral pool areas forming in dune
hollows, and discharge of fill material capable of altering river flows
and sand deposition. Permits for dredge and fill discharge, including
that resulting from construction, are governed by the Army Corps of
Engineers (Corps). Permits for actions likely to affect listed species
receive greater scrutiny, and no discharge of dredged or fill material
shall be permitted if it jeopardizes the continued existence of a
listed species or results in the likelihood of the destruction or
adverse modification of critical habitat (40 CFR 230.10).
Section 10 of the Rivers and Harbors Act (33 U.S.C. 403) requires a
permit from the Corps for any structure or work that takes place in,
under, or over a navigable water or wetland adjacent to navigable
waters of the United States (Army Corps of Engineers, in litt. 2004).
As with the CWA, permits for actions likely to affect listed species
receive greater scrutiny.
The National Environmental Policy Act, as amended (42 U.S.C. 4321-
4347), requires that each Federal agency prepare an environmental
impact statement on the potential environmental consequences of major
actions under their jurisdiction. This does not preclude the agency
from choosing environmentally damaging actions, but it does disclose
the existence of such actions and any less environmentally damaging
alternatives.
The Coastal Zone Management Act (CZMA) (16 U.S.C. 1451-1464) helps
fund State development of comprehensive programs to protect and manage
coastal resources, and requires Federal agencies to act consistently
with those programs.
Finally, the National Wildlife Refuge System Improvement Act of
1997 (Pub. L. 105-57) establishes the protection of biodiversity as the
primary purpose of the national wildlife refuge system. This has lead
to various management actions to benefit Pacific Coast WSP at national
wildlife refuges in the three Pacific coastal States. For instance, the
Don Edwards-San Francisco Bay National Wildlife Refuge has acquired
lands and is working with the Cargill Salt Company to restore historic
salt marsh around San Francisco Bay (M. Kolar, in litt. 2004). Other
coastal refuges in these States provide benefits to plovers and are an
important component of the recovery strategy for the Pacific Coast WSP.
Mexico
Other than the MBTA, the Pacific Coast WSP has no regulatory
protection in Mexico.
Summary of Federal Regulations. Other than the Endangered Species
Act and MBTA, existing U.S. Federal laws and regulations only provide
protection for the Pacific Coast WSP in specific cases, such as where
the species may be impacted by dredge and fill projects. These
protections are therefore applied sporadically throughout the range of
the Pacific Coast WSP, and are currently inadequate to comprehensively
address the threats to the species. Absent the protection accorded due
to its listed status, these statutes and regulations will not provide
sufficient minimal protections for the Pacific Coast WSP. Mexican laws
and regulations are also inadequate to comprehensively address the
threats to the species.
State Laws
State lands administered by the California Department of Parks and
Recreation, California Department of Fish and Game, Oregon Department
of Fish and Wildlife, Oregon Parks and Recreation Department,
Washington Department of Fish and Wildlife, Washington State Parks and
Recreation Commission, and Washington Department of Natural Resources
play an important role in conservation of western snowy plovers and
their habitats. Approximately 21 percent, 12 percent, and 9 percent of
the breeding population of western snowy plover in California, Oregon,
and Washington, respectively, occurs on State lands. Intensive
management for western snowy plovers occurs at a number of State-owned
plover habitat areas.
California
The western snowy plover is a Bird Species of Special Concern in
California. This designation confers no regulatory advantage, but is
associated with recommendations and increased visibility to management
agencies (Remsen 2003).
The California Coastal Management Program, administered by the
California Coastal Commission in accordance with the CZMA includes a
system of: (1) Coastal permits and appeals; (2) planning and
implementation of local coastal programs; and (3) Federal consistency
review. Most local coastal programs and general plans were completed
prior to the 1993 Pacific Coast WSP's listing; therefore, many do not
reflect protective measures specifically for the western snowy plover.
However, it is likely that the
[[Page 20622]]
Pacific Coast WSP has benefited from actions, such as limiting
development, regulated by the California Coastal Commission in some
areas.
In California, biannual western snowy plover coordination meetings
are held among Federal and State agencies and Point Reyes Bird
Observatory staff to track the breeding population of western snowy
plovers in the Monterey Bay area. Meetings of this working group have
been ongoing since 1991. Management needs such as exclosures, symbolic
fencing, predator control, removal of exotic vegetation, and
acquisition of key sites are considered and planned through this forum.
A working group for San Luis Obispo and Santa Barbara Counties,
consisting of site managers, western snowy plover monitors, and our
staff, began meeting twice annually in 2001 to address management needs
of the Pacific Coast WSP. The group is also coordinating window surveys
of breeding and wintering birds in that region.
Management actions of California State Parks along with other
entities. The California State Parks has been a leader with habitat
restoration, monitoring, and the use of symbolic fencing to direct
human use at the beach. Plovers nested at Manchester State Beach for
the first time in 2003, and returned in 2004. A single plover nest was
documented at Gold Bluffs Beach in 2004, which was the first since the
early 1980s. Humboldt County Parks has enacted a ``plover friendly''
ordinance to reduce impacts to breeding plovers. The Bureau of Land
Management and the California Department of Fish and Game also manage
winter and breeding habitat, and have conducted habitat restoration and
human disturbance management (Colwell, et al. 2005).
The California State Parks and the Point Reyes Bird Observatory
have developed some of the leading outreach tools, such as the docent
program implemented at Half Moon Bay State Beach, that have been found
to be effective rangewide. California State Parks and the Point Reyes
Bird Observatory have worked cooperatively with the National Park
Service (Golden Gate National Recreation Area and Point Reyes National
Seashore), the Salinas River National Wildlife Refuge (NWR), and the
California Department of Fish and Game to manage human use in plover
wintering and breeding habitat adjacent to large population centers
(Page, et al., 2005).
The Salinas River NWR, along with California State Parks and Point
Reyes Bird Observatory, has made significant achievements in habitat
and predator management. Symbolic fencing, nest exclosures, lethal and
nonlethal methods of predator control, and outreach techniques have all
been pioneered in this area. Plovers had record reproductive success at
Monterey Bay during 2003 (Page, et al. 2005). Management actions at
Oceano Dunes State Vehicular Recreation Area have also bolstered the
plover numbers. The California State Parks is developing a Habitat
Conservation Plan (HCP) for plovers for the San Luis Obispo District,
including Oceano Dunes State Vehicular Recreation Area.
Oregon
The western snowy plover is listed as threatened under the Oregon
Endangered Species Act (Oregon Administrative Rules (OAR) 635-100-
0125). This OAR protects against actions that would directly kill
plovers (OAR 635-100-0100, 41 ORS 498.026), and also requires the
establishment of ``survival guidelines,'' which in the plover's case
refers to a conservation program defined at OAR 635-105-000. The
program authorizes the preparation of several site-specific management
plans for State lands. State agencies must consult with the Department
of Fish and Wildlife (ODFW) as to whether their actions are consistent
with the local management plan (if one exists), or if not, whether the
actions will appreciably reduce the likelihood of survival or recovery
of the western snowy plover. The action agency makes the final
determination. At this time, the local management plans are not
completed, but an interagency group has been formed to work on them, as
well as on a Statewide habitat conservation plan under section 10 of
the Act, and on coordination of various protective management efforts
such as predator control and monitoring (Lauten, et al. 2006).
Oregon has also developed a coastal zone planning system consistent
with the CZMA, which includes several elements beneficial to western
snowy plovers and their habitat. The system requires local
jurisdictions to develop local comprehensive plans and implementing
measures according to a set of 19 goals. Those goals include
requirements for protection of wildlife habitat, including estuarine,
beach and dune ecosystems, and also encourage planning and coordination
among agencies.
Washington
The snowy plover is listed as endangered under the State endangered
species regulations (Washington Administrative Code 232-12-14), which
authorizes the preparation of a recovery plan for the species. The
State's Shoreline Management Act (RCW 90.58), which enacts coastal zone
management programs applicable to the CZMA, also provides some
protection to the species by requiring local planning efforts to
regulate coastal development. The Shoreline Management Act exempts
single family housing construction from the coastal permit process
(WDOE 1999).
In summary, while State laws and regulations provide some level of
protection for the Pacific Coast WSP, those protections are not
consistent throughout the Pacific Coast WSP's range. As a result, these
existing regulatory mechanisms do not address threats to the Pacific
Coast WSP to such an extent that it is no longer in need of the
protections of the Act.
Local Regulations
In addition to various protections for coastal habitat enacted
under the CZMA related statutes (see above), several local
jurisdictions, such as Half Moon Bay, California, and Coos and Curry
Counties, Oregon, have enacted regulatory policies specifically to
protect the western snowy plover. However, based on results of a
questionnaire sent to local governments, it appears that other local
planning efforts generally do not take the snowy plover into account
(Service 2001). In totality, existing local regulations are inadequate
to address the Pacific Coast WSP's threats to such an extent that it is
no longer in need of the protections of the Act.
Many of these Federal, State, and local regulatory mechanisms were
in place prior to the Federal listing of the Pacific Coast WSP, and
were not adequate to prevent the loss and degradation of Pacific Coast
WSP habitat and decreases in Pacific Coast WSP population numbers, and
therefore, not adequate to preclude the need to list the Pacific Coast
WSP under the Endangered Species Act (Service 1993). While some
significant gains in protection have been made by entities such as
California State Parks, overall, we find that the existing regulatory
mechanisms, beyond the listing itself, have not addressed the threats
facing the Pacific Coast WSP, and are therefore not sufficiently
adequate to warrant delisting of the Pacific Coast WSP. The Endangered
Species Act provides comprehensive conservation of the Pacific Coast
WSP and provides the mechanisms under which we can continue to work
with the States and local governments to implement actions to recover
the species. Delisting would
[[Page 20623]]
remove this most comprehensive means of achieving the eventual recovery
of the species. We thus conclude that the regulatory mechanisms in the
absence of listing are inadequate to address the threats to the Pacific
Coast WSP to such an extent that it is no longer in need of the
protections of the Act.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
The petition did not provide any information about this threat.
However, our information shows that most Pacific Coast WSP nesting
areas occur on unstable sandy substrate which results in weather-
related nest loss, a fairly common natural phenomenon. High tides and
strong winds cause nest losses annually. Events such as extreme high
tides (Wilson 1980; Stenzel et al. 1981), river flooding (Stenzel et
al. 1981; Colwell et al. 2004), and heavy rain (Wilson 1980; Warriner
et al. 1986; Page 1988) have been reported as causes that destroy or
wash away nests. The annual percentage of total nest loss attributed to
weather-related phenomenon has reached 15 to 38 percent at some
locations (Wilson 1980; Warriner et al. 1986). Severe winter storms may
also significantly impact plover populations. For example, after a
series of severe storms during the winter of 1997 to 1998, coinciding
with an El Ni[ntilde]o event (a collection of oceanic and atmospheric
phenomena involving shifted trade winds and warmer ocean waters), the
plover breeding population at VAFB suffered a 10 to 30 percent decline
(Applegate and Schultz 1999). Additionally, erosion of beach sand or
flooding of coastal lagoons or river bars may reduce habitat available
for nesting in some years (Colwell et al. 2005), which likely forces
some plovers to nest in marginal habitat where nesting success is
lower.
Disturbance of nesting or brooding plovers by humans and domestic
animals is a major factor affecting nesting success. Plovers leave
their nests when humans or pets approach too closely. Disturbance
distances that may cause plovers to leave their nests vary widely, from
about 3 to 200 meters (10 to 656 feet) in a Point Reyes, California,
study (Page et al. 1977), and from about 3 to 50 meters (10 to 164
feet) in a study at VAFB, California (Fahy and Woodhouse 1995). Humans
accompanied by dogs tend to elicit stronger avoidance responses than
humans alone (Page et al. 1977; Fahy and Woodhouse 1995; Lafferty
2001). Dogs may also deliberately chase plovers and trample nests
(Lafferty 2001). Repeated flushing of incubating plovers exposes the
eggs to the weather, interrupts foraging, and depletes energy reserves
needed by the adult, which may result in reductions to nesting success
during the breeding season and in reduced survivorship during the
winter (Lafferty 2001).
Surveys at VAFB, from 1994 to 1997, found the rate of nest loss on
southern beaches to be consistently higher than that on north beaches
where recreational use was much lower (Persons and Applegate 1997).
Ruhlen et al. (2003) found that increased human activities at Point
Reyes, California, beaches resulted in a lower plover chick survival
rate. Nests may also be lost directly from human recreational
activities. Warriner et al. (1986) documented a 14 percent loss of
clutches at a Monterey Bay site due to being stepped on, driven over,
or deliberately collected. Motorized vehicles, where allowed onto
stretches of beach used by plovers, can stress or directly kill adults
and chicks, as well as destroy nests and eggs (Colwell et al. 2004).
Plovers' cryptic coloration and habit of crouching in depressions such
as tire tracks make them particularly susceptible to being hit by
vehicles. They are especially vulnerable at night, when they are most
difficult to see. Recent efforts in various areas have been implemented
to isolate nesting plovers from recreational beach users through the
use of docents, symbolic fencing, and public outreach, and have
correlated with higher nesting success in those areas (Page et al.
2003; K. Palermo, in litt. 2004; G. Page, in litt. 2004a).
Motor vehicles that are driven in breeding habitat may result in
the crushing of eggs, chicks, and adults; cause abandonment of nests;
separate chicks from brooding adults; and provide a source of
considerable stress and disturbance to plover family groups and
wintering plovers (J. Myers, in litt. 1988; Stern et al. 1990b; Widrig
1980). In Baja California, Mexico, vehicle traffic at Laguna Ojo de
Liebre has destroyed plover nests and chicks, and the level of off-road
vehicle use was considered ``heavy'' at 3 of 16 nesting areas surveyed
(Palacios et al. 1994). In addition to recreational vehicles, vehicles
used for military activities have also caused western snowy plover
mortality (Powell et al. 1995; Powell et al. 1997; Persons 1994).
Additional recreational activities with potential impacts similar
to those discussed for pedestrians include commercial and surf fishing,
clamming, campfires, and camping. If conducted near a nest, these
activities may result in long-term disturbance and ultimately nest
abandonment (Colwell et. al. 2003).
Plover populations can be negatively impacted by oil spills
(Persons and Applegate 1997; U.S. Bureau of Land Management 2001; Kritz
1999). Oiled plovers lose their ability to regulate their body
temperature and often die of hypothermia or exposure. Additionally,
oiled adults can pass oil onto eggs if they are incubating. Oil on eggs
limits their ability to breathe, and introduces toxic hydrocarbons.
Likewise, oiled adults that attempt to preen inhale and ingest
hydrocarbons. Invertebrate populations are likely reduced as a result
of beaches being oiled, reducing the available plover prey base. Oiled
invertebrates may also be another source of hydrocarbon ingestion for
plovers. During the 1990s, at least six oil spill incidents in
California and one in Oregon resulted in adverse impacts to plovers.
For example, in February 1999, the freighter New Carissa went aground
near the North Jetty of Coos Bay, Oregon, leaking oil from the stern
section on repeated occasions (U.S. Bureau of Land Management 2001).
The incident oiled over 50 percent of the Oregon wintering population
of western snowy plover (Kritz 1999). Had this occurred during nesting
season at one of the major nesting sites the impacts (both from the oil
directly and from subsequent disturbance due to the spill response
crew) could have been extremely severe. Plovers may also be affected by
chronic oil pollution not easily attributable to specific spills.
Intermittent oil spills from unknown sources have been noted on central
California beaches for decades. The cause of some of these spills, such
as those related to periodic oil leakages from the sunken vessel S. S.
Jacob Luckenbach, have recently been identified, while the source of
others remains a mystery (Hampton et al. 2003).
In summary, we conclude that unmanaged human disturbances and
impacts related to oil spills remain a significant threat to the
Pacific Coast WSP. Unmanaged human disturbances that negatively impact
Pacific Coast WSP primarily include disturbance of nesting or brooding
plovers by humans and domestic animals and motorized vehicle use. Oil
spills and their associated clean-up can result in reproductive
failure, direct mortality and injury from being oiled, and
contamination of food sources. The significance of an oil spill to
plovers depends on the extent of the spill, the material spilled, and
the timing of the spill in relation to plover habitat and breeding
chronology.
[[Page 20624]]
Status of the DPS--Conclusion
Threats to the Pacific Coast WSP remain essentially the same as at
the time of its listing in 1993. However, the magnitude of the threats
has been reduced through active management afforded by protections
under the Act, with a resultant increase to the overall Pacific Coast
WSP population. Despite the reduction in the threats' magnitude
relative to the time of listing, the Pacific Coast WSP is still at
risk. The most important threats are ongoing habitat loss and
fragmentation; mortalities, injuries, and disturbance resulting from
human activities; and lack of comprehensive State and local regulatory
mechanisms throughout the range of the WSP. Although overall increases
in plover numbers (which can be attributed to management actions
currently being implemented) have been observed, plover population
sizes are low or plovers are absent throughout parts of their
historical range in Washington, Oregon, and California. Accordingly, we
find that the Pacific Coast WSP continues to qualify as a threatened
species under the Act (see also Finding section below).
We also note that: because some of the threats have been reduced,
the estimated WSP population levels in the United States have increased
over the last 4 years (L. Stenzel, in litt. 2004a); management actions
in several areas appear to be effective (Page et al. 2003; G. Page, in
litt. 2004a); and numerous local management plans, habitat conservation
plans, and integrated natural resource management plans have been
implemented or are in the planning stages (Lauten et al. 2006; Colwell
et al. 2005). We find these trends and management actions encouraging.
We believe significant progress has been made toward recovery in a
relatively short period of time (approximately 10 years), and that
continued implementation of recovery actions that reduce the remaining
threats could justify a delisting of the Pacific Coast WSP in the near
future. In the interim period, we are providing a mechanism that will
afford regulatory relief for areas that are contributing to recovery
now. In today's issue of the Federal Register, we have published a
proposal for a special rule under section 4(d) of the Act that would
exempt certain actions in certain areas from the section 9 take
prohibitions of the Act, throughout the range of the DPS. Please see
the Proposed Rules Section of today's Federal Register for more
information on this proposal.
Finding
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
faced by this species. We reviewed the petition, available published
and unpublished scientific and commercial information, and information
submitted to us during the public comment period following our 90-day
petition finding. This finding reflects and incorporates information we
received during the public comment period and responds to significant
issues. We also consulted with recognized western snowy plover experts
and Federal and State resource agencies. Based on this review, we find
that (1) the Pacific Coast WSP constitutes a valid DPS, which is both
discrete and significant under our DPS policy, (2) delisting of the
Pacific Coast WSP is not warranted due to continued existence of
threats to the DPS and its habitat, and (3) the DPS should remain
classified as threatened. We reviewed the available data and
information on the life history and ecology of the Pacific Coast WSP
and did not find convincing information that the plover was listed in
error or that the threats have changed to such an extent as to warrant
delisting.
In making this determination we have followed the procedures set
forth in section 4(a)(1) of the Act and regulations implementing the
listing provisions of the Act (50 CFR part 424). We recognize that in
the past there have been declines in the distribution and abundance of
the Pacific Coast WSP, primarily attributed to habitat loss and
alteration. Much of the Pacific Coast WSP's historic habitat and range
has been lost or degraded. There is substantial information indicating
that plover habitat continues to be threatened with loss and
fragmentation (listing Factor A) resulting in a negative impact on
plover distribution and abundance. Mortalities and injuries resulting
from human activities that cause continued habitat loss and disturbance
(listing Factors A and E) may be frequent enough to prevent local
recovery of populations, or prevent the re-occupation of suitable
habitat. Although overall increases in plover numbers (which can be
attributed to management actions currently being implemented) have been
observed, plover population sizes are low, and plovers are absent
throughout parts of their historical range in Washington, Oregon, and
California. Although there are some local exemptions, current
regulations (particularly if the protections of the Act are removed)
provide insufficient certainty (listing Factor D) that conservation
efforts will be implemented or that they will be effective in reducing
the level of threat to the Pacific Coast WSP throughout the listed
range.
Therefore we believe that the Pacific Coast WSP DPS is still likely
to become endangered within the foreseeable future. In addition, we
therefore believe (per the analysis conducted as part of the 12 month
status review and the 5-year review) that the Pacific Coast WSP should
remain classified as a threatened species, because it is not extinct,
it is not considered to be recovered, and the original data used for
classification were not in error.
While the finding reflects the analyses conducted to fulfill our
responsibilities under sections 4(b)(3)(A) (status review) and 4(c)(2)
(5-year review) of the Act, we request that you submit any new
information, whenever it becomes available, for this species concerning
status and threats. This information will help us monitor and encourage
the conservation of this species. We intend that any action for the
Pacific coast DPS of the western snowy plover be as accurate as
possible. Therefore, we will continue to accept additional information
and comments from all concerned governmental agencies, the scientific
community, industry, or any other interested party concerning this
finding.
References Cited
A complete list of all references cited is available on request
from the Arcata Fish and Wildlife Office (see ADDRESSES).
Author(s)
The primary author of this document is staff from the Arcata and
Sacramento Fish and Wildlife Offices (see FOR FURTHER INFORMATION
CONTACT).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: April 13, 2006.
H. Dale Hall,
Director, Fish and Wildlife Service.
[FR Doc. 06-3792 Filed 4-20-06; 8:45 am]
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